Declare bzr TERM=dumb to silence progress bars

In theory, one could set BZR_PROGRESS_BAR=none but it does not work in 1.14rc2

tests/bzr-definitions

@@ -1,18 +1,19
 # this file holds the definitions that are used in various bzr tests
 
 "$TESTDIR/hghave" bzr || exit 80
 
+export TERM=dumb
 echo '[extensions]' >> $HGRCPATH
 echo 'convert = ' >> $HGRCPATH
 echo 'hgext.graphlog = ' >> $HGRCPATH
 
 glog()
 {
     hg glog --template '#rev# "#desc|firstline#" files: #files#\n' "$@"
 }
 
 manifest()
 {
     echo "% manifest of $2"
     hg -R $1 manifest -v -r $2
 }